At the end of this year, Minority Leader Nancy Pelosi will lose another close ally — and fellow Californian, no less — in 40-year House veteran Henry A. Waxman.

Sources close to Democratic leadership say they don't suspect that Waxman's retirement, announced Thursday morning, will leave the same gaping hole in Pelosi's carefully-curated inner circle as will the year-end departure of another 20-term California Rep., Education and the Workforce ranking member George C. Miller.

"I've been the Chairman and Ranking Member of this committee before, and I've done both jobs well," Dingell said in a statement sent to CQ Roll Call. "But I just learned of Henry's retirement as I landed at the airport back in Michigan, so I'm going to take a deep breath and look at everything, and from there I'll speak with my colleagues when I return to Washington."

Other likely contenders include the third and fifth most senior Democrats on the panel: Frank Pallone of New Jersey and Anna G. Eshoo of California, respectively. Both of them issued statements on Thursday praising Waxman's tenure and service, but steered clear of discussing their career aspirations. Neither office responded to follow-up requests for comment.

Senior Democratic aides speculate that all three lawmakers are already making phone calls and starting to test the waters of support for ranking member bids, though none could say who stood the greatest chance of success.

Sources say it's within the realm of possibility that Democrats could ultimately defer to Dingell's seniority; the dean of the House is generally well-liked and has made a good effort to get to know the younger members of the House Democratic Caucus.

Others counter that there's no way Dingell can build a groundswell of support strong enough to give him back the ranking member slot: "I don't see how he does it," said one staffer to a senior House Democrat.

That staffer is putting bets on Eshoo, another veteran House member who has special clout with Pelosi.

"Anna Eshoo is on par with George Miller," the staffer said. "Those are [Pelosi's] two closest friends. Period ... I don't think Frank Pallone has that equally strong personal relationship with her."

Though the No. 3 Energy and Commerce Committee Democrat is Rep. Bobby L. Rush, the Chicago Democrat has been taking a leave of absence since last fall and is currently under investigation by the Office of Congressional Ethics.

Apart from the committee leadership jockeying, Democratic aides on Capitol Hill say that Waxman's retirement provides some other food for thought.

One is, can someone fill the void of institutional knowledge he's leaving behind?

"It's regrettable when you don't have someone who is a master legislator still serving," said a Democratic leadership staffer, citing Waxman's work on everything from the Clean Air Act to the ill-fated cap-and-trade bill to the Affordable Care Act.

Another is, does Waxman want to leave office out of some great frustration with Congressional dysfunction and political polarization?

"He specifically cited the Tea Party," said a senior Democratic aide. "That seems to be the theme throughout a lot of these retirements — you can't really get much done so what's the point of sticking around and dealing with ... fundraising, etc., if you can't actually pass substantive legislation?"

Could it be due to fundraising fatigue in the age of the super PAC, exacerbated by California's new "jungle primary" system that is, ironically, weakening some of Pelosi's closest allies who were once safe bets for re-election ?

Or is this all just a sign that the demographics of the House Democratic Caucus are changing? Waxman's own statement suggests age had more to do with it than anything else.

"I am not leaving out of frustration with Congress. Even in today’s environment, there are opportunities to make real progress. ...And I am not leaving because I think House Democrats have no chance to retake the House. House Republicans have no compelling vision for the future. The public understands this, and I am confident that the Democrats can regain control of the House.
“The reason for my decision is simple. After 40 years in Congress, it’s time for someone else to have the chance to make his or her mark, ideally someone who is young enough to make the long-term commitment that’s required for real legislative success."

Simply put, senior members of the caucus are aging, and retirements are simply becoming inevitable.

Some of those members, said one senior Democratic aide, might have been inclined to hang around the House for another term if there was some chance of winning back the chamber in November.

"It's a recognition that '14 is out of reach," the aide said, despite Waxman's own statement to the contrary.

But Pelosi's former long-time chief of staff, John Lawrence, dismissed that theory altogether.

"Those of us who have spent a lot of time in politics know that ten months is a lifetime in politics," Lawrence told CQ Roll Call on Thursday afternoon. "You don't make a career decision in January based on who is going to win an election in November. A whole world can change during that time.

"There's a huge wear and tear that comes from being a member of Congress and you gotta leave at some point," Lawrence continued. "Obviously people draw implications about it, but the fact is, [Miller's and Waxman's seats] are both Democratic seats ... I don't really see a mega-story here in terms of any kind of signal it sends at all."